Okay, this has to be just about the coolest thing I've seen lately.
For a while, before we started using Skype for long distance, we used calling cards. You could get some truly great deals, down to the 1 cent a minute level, in exchange for the annoyance of having to dial a ton of numbers and listening to an advertisement before getting to your actual call.
So I still look online now and then to see what kinds of rates calling cards get. And I ran across a calling card that allows you to fake the caller id that the person you're calling will see. Want them to see the number of the White House? No problem! Or Joe's Pizza Shop? No problem!
The card also allows you to change your voice through an automatic algorithm, in real time. You speak, but what the person on the other end hears is not your voice. You can even have your voice changed so it sounds like you're the opposite gender. All the while displaying a fake caller id.
The voice changing capability has a lot of potential for abuse, but they do keep records enough to be able to track back to you if they are served with a subpoena. Hopefully that will keep the abuse to a minimum.
You can also record calls.
They call the card the Spoof Card, a term carried over from computers, where one computer pretends to be another computer.
A fun idea, but it'll be interesting to see how it works out.
Update: the same company has another calling card I just found, called Liar Card. You make a call with this card and ask the person on the other end a question, and their computers analyze the person's voice stress when they answer the question, and tells you whether they lied or told the truth. According to the web site, it's over 95% accurate.